US5086957A - Molten steel pouring nozzle - Google Patents

Molten steel pouring nozzle Download PDF

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Publication number
US5086957A
US5086957A US07/619,292 US61929290A US5086957A US 5086957 A US5086957 A US 5086957A US 61929290 A US61929290 A US 61929290A US 5086957 A US5086957 A US 5086957A
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US
United States
Prior art keywords
molten steel
pouring nozzle
steel pouring
particle size
average particle
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Expired - Fee Related
Application number
US07/619,292
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English (en)
Inventor
Hidekichi Ozeki
Takafumi Aoki
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Akechi Ceramics Co Ltd
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Akechi Ceramics Co Ltd
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Assigned to AKECHI CERAMICS CO., LTD. reassignment AKECHI CERAMICS CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: AOKI, TAKAFUMI, OZEKI, HIDEKICHI
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/50—Pouring-nozzles
    • B22D41/52—Manufacturing or repairing thereof
    • B22D41/54—Manufacturing or repairing thereof characterised by the materials used therefor
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/48—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates
    • C04B35/482—Refractories from grain sized mixtures

Definitions

  • the present invention relates to a molten steel pouring nozzle which permits effective prevention of reduction or clogging of the bore of the nozzle, through which molten steel flows, when continuously casting an aluminum-killed molten steel containing aluminum.
  • Continuous casting of molten steel is carried out, for example, by pouring molten steel received from a ladle into a tundish, through a molten steel pouring nozzle secured to the bottom wall of the tundish, into a vertical mold arranged below the molten steel pouring nozzle, to form a cast steel strand, and continuously withdrawing the thus formed cast steel strand into a long strand.
  • a nozzle comprising an alumina-graphite refractory is widely used in general.
  • the molten steel pouring nozzle comprising an alumina-graphite refractory has the following problems:
  • non-metallic inclusions such as ⁇ -alumina.
  • the thus produced non-metallic inclusions such as ⁇ -alumina adhere and accumulate onto the surface of the bore of the molten steel pouring nozzle, through which molten steel flows, to clog up the bore, thus making it difficult to achieve stable casting.
  • the non-metallic inclusions such as ⁇ -alumina thus accumulated onto the surface of the bore peel off or fall down, and are entangled into the cast steel strand, thus degrading the quality of the cast steel strand.
  • a larger amount of the ejected inert gas causes entanglement of bubbles produced by the inert gas into the cast steel strand, resulting in the production of defects such as pinholes in a steel product after the completion of rolling. This problem is particularly serious in the casting of molten steel for a high-quality thin steel sheet.
  • a smaller amount of the ejected inert gas causes, on the other hand, adhesion and accumulation of the non-metallic inclusions such as ⁇ -alumina onto the surface of the bore of the molten steel pouring nozzle, thus causing reduction or clogging of the bore.
  • unstabilized zirconia from 35 to 75 wt.%
  • the balance being stabilized zirconia.
  • unstabilized zirconia which is a main constituent of the refractory forming the molten steel pouring nozzle, suffers from a transformation in the crystal structure thereof with an increased thermal expansion coefficient, resulting in the disintegration of crystal grains of unstabilized zirconia.
  • a reduction reaction takes place between unstabilized zirconia having the disintegrated crystal grains and graphite, thus degrading the structure of the refractory.
  • calcium oxide rapidly reacts with non-metallic inclusions such as ⁇ -alumina, which are produced through the reaction of aluminum added as a deoxidizer with oxygen present in molten steel, to produce low-melting-point compounds. Therefore, calcium oxide has a function of preventing the non-metallic inclusions such as ⁇ -alumina from adhering and accumulating onto the surface of the bore of the nozzle.
  • calcium oxide when present alone, violently reacts with water or moisture in the air even at the room temperature to produce calcium hydroxide (Ca(OH) 2 ), which easily disintegrates and tends to become powdery, thus easily causing degradation of the structure of the molten steel pouring nozzle.
  • a content of calcium oxide in said calcium zirconate being within a range of from 23 to 36 weight parts relative to 100 weight parts of said calcium zirconate.
  • the molten steel pouring nozzle of the prior art 3 is formed of a refractory mainly comprising calcium zirconate. Therefore, it is true that contact of calcium oxide contained in calcium zirconate with the produced non-metallic inclusions such as ⁇ -alumina causes the acceleration of reaction between these components, thus producing low-melting-point compounds. Since calcium oxide is not present alone, no degradation of the structure of the molten steel pouring nozzle is caused.
  • An object of the present invention is therefore to provide a molten steel pouring nozzle which permits prevention of reduction or clogging of the bore of the nozzle and degradation of the structure of the refractory forming the nozzle economically and for long period of time without the use of a mechanical means such as the ejection of an inert gas.
  • a molten steel pouring nozzle having, along the axis thereof, a bore through which molten steel flows, wherein:
  • At least part of an inner portion of said molten steel pouring nozzle, which inner portion forms said bore, is formed of a refractory consisting essentially of:
  • zirconia clinker comprising calcium zirconate : from 40 to 89 wt.%
  • a content of calcium oxide in said zirconia clinker being within a range of from 8 to 35 weight parts relative to 100 weight parts of said zirconia clinker;
  • a content of calcium oxide in said calcium silicate being within a range of from 40 to 54 weight parts relative to 100 weight parts of said calcium silicate.
  • FIG. 1 is a schematic vertical sectional view illustrating a first embodiment of the molten steel pouring nozzle of the present invention as an immersion nozzle;
  • FIG. 2 is a schematic vertical sectional view illustrating a second embodiment of the molten steel pouring nozzle of the present invention as an immersion nozzle.
  • zirconia clinker which comprises calcium zirconate, it is possible to inhibit a violent reaction of calcium oxide with water or moisture in the air, thus preventing degradation of the structure of the molten steel pouring nozzle. More particularly, zirconia clinker comprising calcium zirconate and having a prescribed particle size is prepared by melting calcium oxide and zirconia in an electric furnace at a high temperature of at least 1,600° C., then cooling the resultant melt to solidify same, and then pulverizing the resultant solid.
  • the thus prepared zirconia clinker which comprises calcium zirconate (CaO.ZrO 2 ), is stable similarly to stabilized zirconia, and has a low thermal expansion coefficient, and inhibits violent reaction of calcium oxide with water or moisture in the air, thus preventing degradation of the structure of the molten steel pouring nozzle.
  • calcium silicate has a function of replenishing the quantity of calcium oxide, which is to react with ⁇ -alumina in molten steel.
  • At least part of an inner portion of the molten steel pouring nozzle of the present invention, which inner portion forms a bore thereof, is formed of a refractory consisting essentially of:
  • zirconia clinker comprising calcium zirconate : from 40 to 89 wt.%
  • a content of calcium oxide in said zirconia clinker being within a range of from 8 to 35 weight parts relative to 100 weight parts of said zirconia clinker;
  • calcium silicate from 1 to 25 wt.%, where, a content of calcium oxide in said calcium silicate being within a range of from 40 to 54 weight parts relative to 100 weight parts of said calcium silicate.
  • Zirconia clinker has a low thermal expansion coefficient and is excellent in spalling resistance.
  • a content of zirconia clinker of under 40 wt.% however, the amount of calcium oxide, which is to react with the non-metallic inclusions such as ⁇ -alumina in molten steel, becomes insufficient, thus making it impossible to prevent adhesion and accumulation of the non-metallic inclusions such as ⁇ -alumina onto the surface of the bore of the molten steel pouring nozzle.
  • a content of zirconia clinker of over 89 wt.% on the other hand, there occurs abnormality in the thermal expansion coefficient and at a temperature of at least about 900° C., and spalling resistance is deteriorated.
  • zirconia clinker should therefore be limited within a range of from 40 to 89 wt.%.
  • Zirconia clinker should preferably have an average particle size of up to 44 ⁇ m in order to ensure a satisfactory surface smoothness of the nozzle.
  • a content of calcium oxide in zirconia clinker of over 35 weight parts relative to 100 weight parts of zirconia clinker on the other hand, calcium oxide, which is not dissolved into calcium zirconate, and reacts violently with water or moisture in the air, and has a high thermal expansion coefficient, is present alone in zirconia clinker, resulting in degradation of the structure of the molten steel pouring nozzle.
  • the content of calcium oxide in zirconia clinker should therefore be limited within a range of from 8 to 35 weight parts relative to 100 weight parts of zirconia clinker.
  • Graphite has a function of improving oxidation resistance of a refractory and wetting resistance thereof against molten steel, and increasing thermal conductivity of the refractory. Particularly, natural graphite is suitable for obtaining the above-mentioned function. With a content of graphite of under 10 wt.%, however, a desired effect as described above cannot be obtained, and spalling resistance is poor. With a content of graphite of over 35 wt.%, on the other hand, corrosion resistance is degraded. The content of graphite should therefore be limited within a range of from 10 to 35 wt.%. Graphite should preferably have an average particle size of up to 5 500 ⁇ m with a view to improving the above-mentioned function.
  • Calcium silicate (CaO.SiO2) has a function of promoting calcium oxide in each particle of zirconia clinker to move toward the surface of each particle of zirconia clinker and to gather there. Calcium silicate has furthermore a function of replenishing the quantity of calcium oxide, which is to react with ⁇ -alumina in molten steel. With a content of calcium silicate of under 1 wt.%, however, a desired effect as described above cannot be obtained. With a content of calcium silicate of over 25 wt.%, on the other hand, the structure of the refractory is degraded, thus leading to a lower corrosion resistance and a lower refractoriness.
  • the content of calcium silicate should therefore be limited within a range of from 1 to 25 wt.%, and more preferably, within a range of from 2 to 20 wt.%.
  • calcium silicate should preferably have an average particle size of up to 44 ⁇ m.
  • calcium silicate for example, calcium metasilicate comprising 48.3 wt.% CaO and 51.7 wt.% SiO 2 may be used.
  • Calcium oxide contained in calcium silicate (CaO.SiO 2 ) has a function of replenishing the quantity of calcium oxide in zirconia clinker, which is to react with ⁇ -alumina in molten steel.
  • a molar ratio of calcium oxide to silica in calcium silicate is 1 : 1, calcium oxide contained in calcium silicate never reacts violently with water or moisture in the air.
  • a content of calcium oxide in calcium silicate of under 40 weight parts relative to 100 weight parts of calcium silicate, there is unavailable a desired effect as described above of replenishing the quantity of calcium oxide in zirconia clinker.
  • silicon carbide may further be added.
  • FIG. 1 is a schematic vertical sectional view illustrating a first embodiment of the molten steel pouring nozzle of the present invention as an immersion nozzle.
  • the molten steel pouring nozzle of the first embodiment is used as an immersion nozzle which is arranged between a tundish and a vertical mold arranged below the tundish.
  • the molten steel pouring nozzle 4 of the first embodiment of the present invention has, along the axis thereof, a bore 1 through which molten steel flows.
  • An inner portion 2 of the molten steel pouring nozzle 4, which forms the bore 1, is formed of a refractory having the above-mentioned chemical composition.
  • An outer portion 3 surrounding the inner portion 2 is formed of a refractory, for example, an alumina-graphite refractory having an excellent erosion resistance against molten steel.
  • a refractory for example, an alumina-graphite refractory having an excellent erosion resistance against molten steel.
  • FIG. 2 is a schematic vertical sectional view illustrating a second embodiment of the molten steel pouring nozzle of the present invention as an immersion nozzle.
  • a molten steel pouring nozzle 4 of the second embodiment of the present invention is identical in construction to the above-mentioned molten steel pouring nozzle 4 of the first embodiment of the present invention, except that the whole of a lower portion of the molten steel pouring nozzle 4, which forms a lower portion of a bore 1, is formed of a refractory having the above-mentioned chemical composition. Therefore, the same reference numerals are assigned to the same components as those in the first embodiment, and the description thereof is omitted.
  • the molten steel pouring nozzle 4 of the second embodiment has a service life longer than that of the molten steel pouring nozzle 4 of the first embodiment, since the refractory having the above-mentioned chemical composition, which forms the lower portion of the bore 1, where reaction between calcium oxide and the non-metallic inclusions such as ⁇ -alumina takes place most actively, has a sufficient thickness as shown in FIG. 2.
  • phenol resin in the state of powder and liquid was added in an amount within a range of from 5 to 10 wt.%, to each of blended raw materials Nos. 1 to 4 including the above-mentioned zirconia clinker comprising calcium zirconate, having the chemical compositions within the scope of the present invention as shown in Table 1.
  • blended raw materials Nos. 1 to 4 added with phenol resin was mixed and kneaded to obtain a kneaded mass.
  • phenol resin in the state of powder and liquid was added in an amount within a range of from 5 to 10 wt.%, to each of blended raw materials Nos. 5 to 9 including the above-mentioned zirconia clinker, having the chemical compositions outside the scope of the present invention as shown in Table 1.
  • Each of these blended raw materials Nos. 5 to 9 added with phenol resin was mixed and kneaded to obtain a kneaded mass.
  • the results ar shown in Table 2.
  • the results are also shown in Table 2.
  • the sample for comparison No. 5 has a high erosion ratio when there is no adhesion of the non-metallic inclusion such as ⁇ -alumina. More specifically, the sample for comparison No. 5 is very poor in spalling resistance, since the content of zirconia clinker comprising calcium zirconate is high outside the scope of the present invention. In addition, the sample for comparison No. 5 has a large amount of adhesion of the non-metallic inclusions such as ⁇ -alumina, since calcium silicate is not contained. The sample for comparison No. 6 is very poor in corrosion resistance against molten steel, since the content of calcium silicate is high outside the scope of the present invention. The sample for comparison No.
  • the molten steel pouring nozzle of the present invention as described above in detail, it is possible to stably inhibit reduction or clogging of the bore of the nozzle caused by adhesion of the non-metallic inclusions such as ⁇ -alumina for a long period of time without causing degradation of the structure of the refractory.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Ceramic Engineering (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • Continuous Casting (AREA)
US07/619,292 1990-01-23 1990-11-28 Molten steel pouring nozzle Expired - Fee Related US5086957A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2-14218 1990-01-23
JP2014218A JPH03221249A (ja) 1990-01-23 1990-01-23 連続鋳造用浸漬ノズル

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US (1) US5086957A (cs)
JP (1) JPH03221249A (cs)
AT (1) AT404567B (cs)
CA (1) CA2031378C (cs)
DE (1) DE4100352A1 (cs)
FR (1) FR2657279B1 (cs)
GB (1) GB2240498B (cs)
IT (1) IT1244198B (cs)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2686534A1 (fr) * 1992-01-27 1993-07-30 Tokyo Yogyo Kk Buse de coulee de l'acier fondu.
US5691061A (en) * 1994-06-15 1997-11-25 Vesuvius Crucible Company Refractory shape having an external layer capable of forming a layer impermeable to gases and process for its preparation
US5902511A (en) * 1997-08-07 1999-05-11 North American Refractories Co. Refractory composition for the prevention of alumina clogging
US6012508A (en) * 1996-09-16 2000-01-11 Ishikawajima-Harima Heavy Indistries Limited Strip casting
CN1048932C (zh) * 1994-06-15 2000-02-02 维苏威乌斯法国公司 能形成不透气的外料层的浇注件及其制造方法
WO2001070434A1 (en) * 2000-03-17 2001-09-27 Vesuvius Crucible Company Anti-buildup liner for refractory shapes
US6321953B1 (en) * 1996-04-11 2001-11-27 Shinagawa Refractories, Co., Ltd. Composite immersion nozzle
US20050274486A1 (en) * 2002-08-20 2005-12-15 Koji Ogata Method for manufacturing immersion nozzle less susceptible to deposition of alumina for use in continuous casting

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0747198B2 (ja) * 1992-02-24 1995-05-24 明智セラミックス株式会社 溶鋼の連続鋳造用ノズル
JPH07214259A (ja) * 1994-01-25 1995-08-15 Akechi Ceramics Kk 溶鋼の連続鋳造用ノズル
US5681499A (en) * 1994-06-15 1997-10-28 Vesuvius Crucible Company Method and compositions for making refractory shapes having dense, carbon free surfaces and shapes made therefrom
JP5920412B2 (ja) * 2014-07-17 2016-05-18 品川リフラクトリーズ株式会社 連続鋳造ノズル

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Publication number Priority date Publication date Assignee Title
US3722821A (en) * 1971-06-03 1973-03-27 Bell Telephone Labor Inc Devices for processing molten metals
JPS5771860A (en) * 1980-10-24 1982-05-04 Kurosaki Refractories Co Cao-containing graphitic casting nozzle
JPS62148076A (ja) * 1985-12-23 1987-07-02 Akechi Ceramics Kk 連続鋳造用ノズル
US4780434A (en) * 1984-10-02 1988-10-25 Toshiba Ceramics, Co., Ltd. Refractory composition
JPS6440154A (en) * 1987-08-07 1989-02-10 Akechi Ceramics Kk Nozzle for continuous casting
US4989762A (en) * 1989-02-07 1991-02-05 Akechi Ceramics Co., Ltd. Molten steel pouring nozzle

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SU637387A1 (ru) * 1977-05-05 1978-12-15 Украинский научно-исследовательский институт огнеупоров Шихта дл изготовлени огнеупорных изделий
JPS5919075B2 (ja) * 1979-09-05 1984-05-02 品川白煉瓦株式会社 連続鋳造用浸漬ノズル
DE2936480C2 (de) * 1979-09-10 1983-11-03 Akechi Taikarenga K.K., Ena, gifu Feuerfester Werkstoff für einen Tauchausguß
JPS58107252U (ja) * 1981-12-10 1983-07-21 品川白煉瓦株式会社 連続鋳造用浸漬ノズル
FR2533208B1 (fr) * 1982-09-22 1986-08-01 Produits Refractaires Composition refractaire moulable a base de zircone partiellement stabilisee et d'un liant hydraulique alumineux, sa preparation et pieces fabriquees a partir de cette composition
JPS59162174A (ja) * 1983-03-07 1984-09-13 ハリマセラミック株式会社 連続鋳造用ノズルの製造方法
US4568007A (en) * 1984-01-23 1986-02-04 Vesuvius Crucible Company Refractory shroud for continuous casting
JPS6228816A (ja) * 1985-07-31 1987-02-06 Fuji Kiko Co Ltd シフト装置
JPS62288161A (ja) * 1986-06-05 1987-12-15 黒崎窯業株式会社 ＺｒＯ↓２−ＣａＯ含有連続鋳造用浸漬ノズルの製造方法
JP2542585B2 (ja) * 1986-08-08 1996-10-09 東芝セラミツクス株式会社 連続鋳造用浸漬ノズル
JPS63162566A (ja) * 1986-12-24 1988-07-06 美濃窯業株式会社 塩基性耐火組成物
JPH0289546A (ja) * 1988-09-26 1990-03-29 Kawasaki Refract Co Ltd 連続鋳造用ノズル
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Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3722821A (en) * 1971-06-03 1973-03-27 Bell Telephone Labor Inc Devices for processing molten metals
JPS5771860A (en) * 1980-10-24 1982-05-04 Kurosaki Refractories Co Cao-containing graphitic casting nozzle
US4780434A (en) * 1984-10-02 1988-10-25 Toshiba Ceramics, Co., Ltd. Refractory composition
JPS62148076A (ja) * 1985-12-23 1987-07-02 Akechi Ceramics Kk 連続鋳造用ノズル
JPS6440154A (en) * 1987-08-07 1989-02-10 Akechi Ceramics Kk Nozzle for continuous casting
US4989762A (en) * 1989-02-07 1991-02-05 Akechi Ceramics Co., Ltd. Molten steel pouring nozzle

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2686534A1 (fr) * 1992-01-27 1993-07-30 Tokyo Yogyo Kk Buse de coulee de l'acier fondu.
US5244130A (en) * 1992-01-27 1993-09-14 Akechi Ceramics Co., Ltd. Molten steel pouring nozzle
US5691061A (en) * 1994-06-15 1997-11-25 Vesuvius Crucible Company Refractory shape having an external layer capable of forming a layer impermeable to gases and process for its preparation
CN1048932C (zh) * 1994-06-15 2000-02-02 维苏威乌斯法国公司 能形成不透气的外料层的浇注件及其制造方法
US6321953B1 (en) * 1996-04-11 2001-11-27 Shinagawa Refractories, Co., Ltd. Composite immersion nozzle
US6012508A (en) * 1996-09-16 2000-01-11 Ishikawajima-Harima Heavy Indistries Limited Strip casting
US5902511A (en) * 1997-08-07 1999-05-11 North American Refractories Co. Refractory composition for the prevention of alumina clogging
WO2001070434A1 (en) * 2000-03-17 2001-09-27 Vesuvius Crucible Company Anti-buildup liner for refractory shapes
US6537486B1 (en) 2000-03-17 2003-03-25 Yesuvius Crucible Company Anti-buildup liner
US20050274486A1 (en) * 2002-08-20 2005-12-15 Koji Ogata Method for manufacturing immersion nozzle less susceptible to deposition of alumina for use in continuous casting

Also Published As

Publication number Publication date
IT1244198B (it) 1994-07-08
FR2657279A1 (fr) 1991-07-26
JPH03221249A (ja) 1991-09-30
JPH0478392B2 (cs) 1992-12-11
DE4100352C2 (cs) 1993-06-17
GB2240498B (en) 1993-10-06
CA2031378C (en) 1996-09-03
GB2240498A (en) 1991-08-07
FR2657279B1 (fr) 1994-01-14
AT404567B (de) 1998-12-28
IT9022429A1 (it) 1992-06-19
GB9100059D0 (en) 1991-02-20
ATA4391A (de) 1998-05-15
CA2031378A1 (en) 1991-07-24
DE4100352A1 (de) 1991-07-25

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